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Byambaragchaa M, Choi SH, Joo HE, Kim SG, Kim YJ, Park GE, Kang MH, Min KS. Specific Biological Activity of Equine Chorionic Gonadotropin (eCG) Glycosylation Sites in Cells Expressing Equine Luteinizing Hormone/CG (eLH/CG) Receptor. Dev Reprod 2021; 25:199-211. [PMID: 35141446 PMCID: PMC8807129 DOI: 10.12717/dr.2021.25.4.199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/02/2021] [Accepted: 11/23/2021] [Indexed: 11/30/2022]
Abstract
Equine chorionic gonadotropin (eCG), produced by the endometrial cups of the
placenta after the first trimester, is a specific glycoprotein that displays
dual luteinizing hormone (LH)-like and follicle-stimulating hormone (FSH)-like
effects in non-equid species. However, in equidaes, eCG exhibits only LH-like
activity. To identify the specific biological functions of glycosylated sites in
eCG, we constructed the following site mutants of N- and O-linked glycosylation:
eCGβ/αΔ56, substitution of α-subunit56
N-linked glycosylation site; eCGβ-D/α, deletion of the O-linked
glycosylation sites at the β-subunit, and
eCGβ-D/αΔ56, double mutant. We produced recombinant eCG
(rec-eCG) proteins in Chinese hamster ovary suspension (CHO-S) cells. We
examined the biological activity of rec-eCG proteins in CHO-K1 cells expressing
the eLH/CG receptor and found that signal transduction activities of
deglycosylated mutants remarkably decreased. The EC50 levels of
eCGβ/αΔ56, eCGβ-D/α, and
eCGβ-D/αΔ56 mutants decreased by 2.1-, 5.6-, and 3.4-fold,
respectively, compared to that of wild-type eCG. The Rmax values of the mutants
were 56%-80% those of wild-type eCG (141.9 nmol/104 cells). Our
results indicate that the biological activity of eCG is greatly affected by the
removal of N- and O-linked glycosylation sites in cells expressing eLH/CGR.
These results provide important information on rec-eCG in the regulation of
specific glycosylation sites and improve our understanding of the specific
biological activity of rec-eCG glycosylation sites in equidaes.
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Affiliation(s)
| | - Seung-Hee Choi
- Animal Biotechnology, Hankyong National University, Ansung 17579, Korea
| | - Hyo-Eun Joo
- Dept. of Animal Life Science, Hankyong National University, Ansung 17579, Korea
| | - Sang-Gwon Kim
- Dept. of Animal Life Science, Hankyong National University, Ansung 17579, Korea
| | - Yean-Ji Kim
- Dept. of Animal Life Science, Hankyong National University, Ansung 17579, Korea
| | - Gyeong-Eun Park
- Dept. of Animal Life Science, Hankyong National University, Ansung 17579, Korea
| | - Myung-Hwa Kang
- Dept. of Food Science and Nutrition, Hoseo University, Asan 31499, Korea
| | - Kwan-Sik Min
- Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea.,Animal Biotechnology, Hankyong National University, Ansung 17579, Korea.,Dept. of Animal Life Science, Hankyong National University, Ansung 17579, Korea
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Lee SY, Byambaragchaa M, Choi SH, Kang HJ, Kang MH, Min KS. Roles of N-linked and O-linked glycosylation sites in the activity of equine chorionic gonadotropin in cells expressing rat luteinizing hormone/chorionic gonadotropin receptor and follicle-stimulating hormone receptor. BMC Biotechnol 2021; 21:52. [PMID: 34482828 PMCID: PMC8419929 DOI: 10.1186/s12896-021-00712-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 09/01/2021] [Indexed: 12/04/2022] Open
Abstract
Background Equine chorionic gonadotropin (eCG), which comprises highly glycosylated α-subunit and β-subunit, is a unique member of the glycoprotein hormone family as it elicits both follicle-stimulating hormone (FSH)-like and luteinizing hormone (LH)-like responses in non-equid species. To examine the biological function of glycosylated sites in eCG, the following glycosylation site mutants were constructed: eCGβ/αΔ56, substitution of Asn56 of α-subunit with Gln; eCGβ-D/α, deletion of the O-linked glycosylation site at the carboxyl-terminal peptide (CTP) region of the β-subunit; eCGβ-D/αΔ56, double mutant. The recombinant eCG (rec-eCG) mutants were expressed in Chinese hamster ovary suspension (CHO-S) cells. The FSH-like and LH-like activities of the mutants were examined using CHO-K1 cells expressing rat lutropin/CG receptor (rLH/CGR) and rat FSH receptor (rFSHR). Results Both rec-eCGβ/α and rec-eCGβ/αΔ56 were efficiently secreted into the CHO-S cell culture medium on day 1 post-transfection. However, the secretion of eCGβ-D/α and eCGβ-D/αΔ56, which lack approximately 12 O-linked glycosylation sites, was slightly delayed. The expression levels of all mutants were similar (200–250 mIU/mL) from days 3 to 7 post-transfection. The molecular weight of rec-eCGβ/α, rec-eCGβ/αΔ56 and rec-eCG β-D/α were in the ranges of 40–45, 37–42, and 34–36 kDa, respectively. Treatment with peptide-N-glycanase F markedly decreased the molecular weight to approximately 5–10 kDa. Rec-eCGβ/αΔ56 exhibited markedly downregulated LH-like activity. The signal transduction activity of both double mutants was completely impaired. This indicated that the glycosylation site at Asn56 of the α-subunit plays a pivotal role in the LH-like activity of eCG. Similarly, the FSH-like activity of the mutants was markedly downregulated. eCGβ-D/α exhibited markedly downregulated LH-like and FSH-like activities. Conclusions Rec-eCGβ/α exhibits potent biological activity in cells expressing rLH/CGR and rFSHR. The findings of this study suggest that the LH-like and FSH-like activities of eCG are regulated by the N-linked glycosylation site at Asn56 of the eCG α-subunit and/or by the O-linked glycosylation sites of the eCG β-subunit. These findings improved our understanding of the mechanisms underlying both LH-like and FSH-like activities of eCG.
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Affiliation(s)
- So-Yun Lee
- Animal Biotechnology, Graduate School of Future Convergence Technology, Institute of Genetic Engineering, Hankyong National University, Ansung, 17579, Korea
| | - Munkhzaya Byambaragchaa
- Animal Biotechnology, Graduate School of Future Convergence Technology, Institute of Genetic Engineering, Hankyong National University, Ansung, 17579, Korea
| | - Seung-Hee Choi
- Animal Biotechnology, Graduate School of Future Convergence Technology, Institute of Genetic Engineering, Hankyong National University, Ansung, 17579, Korea
| | - Han-Ju Kang
- Animal Biotechnology, Graduate School of Future Convergence Technology, Institute of Genetic Engineering, Hankyong National University, Ansung, 17579, Korea
| | - Myung-Hwa Kang
- Department of Food Science and Nutrition, Hoseo University, Asan, 31499, Korea
| | - Kwan-Sik Min
- Animal Biotechnology, Graduate School of Future Convergence Technology, Institute of Genetic Engineering, Hankyong National University, Ansung, 17579, Korea. .,School of Animal Life Biotechnology, Institute of Genetic Engineering, Hankyong National University, Ansung, 17579, Korea.
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Byambaragchaa M, Park A, Gil SJ, Lee HW, Ko YJ, Choi SH, Kang MH, Min KS. Luteinizing hormone-like and follicle-stimulating hormone-like activities of equine chorionic gonadotropin β-subunit mutants in cells expressing rat luteinizing hormone/chorionic gonadotropin receptor and rat follicle-stimulating hormone receptor. Anim Cells Syst (Seoul) 2021; 25:171-181. [PMID: 34262660 PMCID: PMC8253215 DOI: 10.1080/19768354.2021.1943708] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
To identify the specific region of eCG involved in FSH-like activity, the following mutant expression vectors were constructed targeting the amino acid residues 102–104 of the eCG β-subunit: single mutants, eCGβV102G/α, eCGβF103P/α, and eCGβR104K/α; double mutants, eCGβV102G;F103P/α, eCGβV102G;R104K/α, and eCGβF103P;R104K/α; triple mutant, eCGβV102G;F103P;R104K/α. The LH-like and FSH-like activities of eCG mutants were examined in CHO-K1 cells expressing rat LH/CG receptor and rat FSH receptor. The levels of eCGβV102G/α, eCGβR104K/α, and eCGβV102G;R104K/α in the culture supernatant were markedly lower than those of eCGβ/α-wt. The other mutants and rec-eCGβ/α-wt were efficiently secreted into the culture supernatant. The LH-like activities of eCGV104G/α, eCGβV102G;R104K/α, and eCGβF103P;R104K/α were approximately 61%, 52%, and 54%, respectively, of those of eCG-wt. The Rmax values of the mutants were 58.9%–78.8% those of eCG-wt with eCGβR104K/α exhibiting the lowest value. The FSH-like activities of single mutants were only 16%–20% of those of eCG-wt. Additionally, the FSH-like activity of double mutants was less than 10% of that of eCG-wt. In particular, the FSH-like activities of βV102G;R104K/α and βF103P;R104K/α were 2.5–2.9% of that of eCG-wt. These results suggest that the amino acid residues 102–104 of the eCG β-subunit are dispensable and that the residue 104 of the eCG β-subunit plays a pivotal role in signal transduction through the rat FSH receptor. Thus, these mutants may aid future studies on eCG interactions with mammalian FSH receptors in vitro and in vivo.
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Affiliation(s)
- Munkhzaya Byambaragchaa
- Animal Life and Environmental Science, Institute of Genetic Engineering, Hankyong National University, Ansung, Korea
| | - Ayoung Park
- Animal Life and Environmental Science, Institute of Genetic Engineering, Hankyong National University, Ansung, Korea
| | - So-Jin Gil
- School of Animal Life Biotechnology, Hankyong National University, Ansung, Korea
| | - Hae-Won Lee
- School of Animal Life Biotechnology, Hankyong National University, Ansung, Korea
| | - Yun-Jeong Ko
- School of Animal Life Biotechnology, Hankyong National University, Ansung, Korea
| | - Seung-Hee Choi
- Animal Life and Environmental Science, Institute of Genetic Engineering, Hankyong National University, Ansung, Korea
| | - Myung-Hwa Kang
- Department of Food Science and Nutrition, Hoseo University, Asan, Korea
| | - Kwan-Sik Min
- Animal Life and Environmental Science, Institute of Genetic Engineering, Hankyong National University, Ansung, Korea.,School of Animal Life Biotechnology, Hankyong National University, Ansung, Korea
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Park JJ, Seong HK, Kim JS, Munkhzaya B, Kang MH, Min KS. Internalization of Rat FSH and LH/CG Receptors by rec-eCG in CHO-K1 Cells. Dev Reprod 2017; 21:111-120. [PMID: 28791335 PMCID: PMC5532303 DOI: 10.12717/dr.2017.21.2.111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 03/23/2017] [Accepted: 03/25/2017] [Indexed: 11/17/2022]
Abstract
Equine chorionic gonadotropin (eCG) is a unique molecule that elicits the response characteristics of both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in other species. Previous studies from this laboratory had demonstrated that recombinant eCG (rec-eCG) from Chinese hamster ovary (CHO-K1) cells exhibited both FSH- and LH-like activity in rat granulosa and Leydig cells. In this study, we analyzed receptor internalization through rec-eCGs, wild type eCG (eCGβ/α) and mutant eCG (eCGβ/αΔ56) with an N-linked oligosaccharide at Asn56 of the α-subunit. Both the rec-eCGs were obtained from CHO-K1 cells. The agonist activation of receptors was analyzed by measuring stimulation time and concentrations of rec-eCGs. Internalization values in the stably selected rat follicle-stimulating hormone receptor (rFSHR) and rat luteinizing/chorionic gonadotropin receptor (rLH/CGR) were highest at 50 min after stimulation with 10 ng of rec-eCGβ/α. The dose-dependent response was highest when 10 ng of rec-eCGβ/α was used. The deglycosylated eCGβ/αΔ56 mutant did not enhance the agonist-stimulated internalization. We concluded that the state of activation of rFSHR and rLH/CGR could be modulated through agonist-stimulated internalization. Our results suggested that the eLH/CGRs are mostly internalized within 60 min by agonist-stimulation by rec-eCG. We also suggested that the lack of responsiveness of the deglycosylated eCGβ/ αΔ56 was likely because the site of glycosylation played a pivotal role in agonist-stimulated internalization in cells expressing rFSHR and rLH/CGR.
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Affiliation(s)
- Jong-Ju Park
- Animal Biotechnology, Graduate School of Future Convergence Technology, Department of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
| | - Hun-Ki Seong
- Animal Biotechnology, Graduate School of Future Convergence Technology, Department of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
| | - Jeong-Soo Kim
- Animal Biotechnology, Graduate School of Future Convergence Technology, Department of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
| | - Byambaragchaa Munkhzaya
- Animal Biotechnology, Graduate School of Future Convergence Technology, Department of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
| | - Myung-Hwa Kang
- Department of Food Science and Nutrition, Hoseo University, Asan 31499, Korea
| | - Kwan-Sik Min
- Animal Biotechnology, Graduate School of Future Convergence Technology, Department of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
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Klett D, Meslin P, Relav L, Nguyen TMD, Mariot J, Jégot G, Cahoreau C, Combarnous Y. Low reversibility of intracellular cAMP accumulation in mouse Leydig tumor cells (MLTC-1) stimulated by human Luteinizing Hormone (hLH) and Chorionic Gonadotropin (hCG). Mol Cell Endocrinol 2016; 434:144-53. [PMID: 27373440 DOI: 10.1016/j.mce.2016.06.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 06/27/2016] [Accepted: 06/28/2016] [Indexed: 11/17/2022]
Abstract
In order to study the intracellular cAMP response kinetics of Leydig cells to hormones with LH activity, we used MLTC-1 cells transiently expressing a chimeric cAMP-responsive luciferase so that real-time variations of intracellular cAMP concentration could be followed using oxiluciferin luminescence produced from catalyzed luciferin oxidation. The potencies of the different LHs and CGs were evaluated using areas under the curves (AUC) of their kinetics over 60 min stimulation. All mammalian LHs and CGs tested were found to stimulate cAMP accumulation in these cells. The reversibility of this stimulation was studied by removing the hormone from the culture medium after 10 min of incubation. The ratios of kinetics AUC after removing or not the hormone were used to evaluate the stimulation reversibility of each hormone. Natural and recombinant hLHs and hCGs were found to exhibit slowly reversible activation compared to pituitary rat, ovine, porcine, camel and equine LHs, serum-derived eCG (PMSG) and recombinant eLH/CGs. Carbohydrate side chains are not involved in this phenomenon since natural and recombinant homologous hormones exhibit the same reversibility rates. It is still unknown whether only one human subunit, α or β, is responsible for this behaviour or whether it is due to a particular feature of the hLH and hCG quaternary structure.
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Affiliation(s)
- Danièle Klett
- INRA, CNRS, Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France
| | - Philippine Meslin
- INRA, CNRS, Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France
| | - Lauriane Relav
- INRA, CNRS, Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France
| | - Thi Mong Diep Nguyen
- INRA, CNRS, Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France; Quy Nhon University, Viet Nam
| | - Julie Mariot
- INRA, CNRS, Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France
| | - Gwenhaël Jégot
- INRA, CNRS, Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France
| | - Claire Cahoreau
- INRA, CNRS, Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France
| | - Yves Combarnous
- INRA, CNRS, Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France.
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Saleh M, Shahin M, Wuttke W, Gauly M, Holtz W. Pharmacokinetics of human chorionic gonadotropin after i.m. administration in goats (Capra hircus). Reproduction 2012; 144:77-81. [PMID: 22573828 DOI: 10.1530/rep-12-0093] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The present investigation addresses the pharmacokinetics of human chorionic gonadotropin (hCG), intramuscularly (i.m.) administered to goats. Nine pluriparous does of the Boer goat breed, 2-6 years of age and weighing 45-60 kg, were administered 500 IU hCG (2 ml Chorulon) deep into the thigh musculature 18 h after superovulatory FSH treatment. Blood samples were drawn from the jugular vein at 2 h intervals for the first 24h, at 6 h intervals until 42 h, and at 12 h intervals until 114 h after administration. After centrifugation, plasma hCG concentrations were determined by electrochemiluminescence immunoassay. Pharmacokinetical parameters were as follows: lag time, 0.4 (s.e.m. 0.1) h; absorption rate constant, 0.34 (s.e.m. 0.002) h; absorption half-life, 2.7 (s.e.m. 0.5) h; elimination rate constant, 0.02 (s.e.m. 0.002) h; biological half-life, 39.4 (s.e.m. 5.1) h; and apparent volume of distribution, 16.9 (s.e.m. 4.3) l. The plasma hCG profile was characterized by an absorption phase of 11.6 (s.e.m. 1.8) h and an elimination phase of 70.0 (s.e.m. 9.8) h, with considerable individual variation in bioavailability and pharmacokinetical parameters. Biological half-life was negatively correlated (P<0.05) with peak concentration (r=-0.76), absorption rate constant (r=-0.78), and elimination rate constant (r=-0.87). The results indicate that after rapid absorption, hCG remains in the circulation for an extended period. This has to be taken into account when assessing the stimulatory response to hCG treatment on an ovarian level.
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Affiliation(s)
- M Saleh
- Department of Animal Science, Georg-August-University, Albrecht-Thaer-Weg 3, 37075 Goettingen, Germany
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Min KS, Hiyama T, Seong HH, Hattori N, Tanaka S, Shiota K. Biological Activities of Tethered Equine Chorionic Gonadotropin (eCG) and Its Deglycosylated Mutants. J Reprod Dev 2004; 50:297-304. [PMID: 15226594 DOI: 10.1262/jrd.50.297] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Equine chorionic gonadotropin (eCG), which consists of highly glycosylated alpha- and beta-subunits, is a unique member of the gonadotropin family because it elicits response characteristics of both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in species other than the horse. In this study, recombinant tethered-eCG as well as its deglycosylated mutants were produced to determine if alpha- and beta- subunits can be synthesized as a single polypeptide chain (tethered-eCG) and display biological activity. We found that tethered-eCG (T- betaalpha) had both LH- and FSH-like activities comparable to dimeric eCG. Luteinizing hormone-like activity of tethered-eCGs deglycosylated at Asn(56) (T-betaalpha56) was decreased. In contrast, LH-like activity of eCG without O-glycosylated carboxyl-terminal peptide (CTP) (T-betacalpha) was slightly decreased but still similar to T-betaalpha. Double mutation at Asn(56) and CTP (T-betacalpha56) caused marked decrease in the activity, indicating that both glycosylations at Asn(56) and CTP are involved in LH-like activity in the tethered form. Interestingly, FSH-like activity remained in all deglycosylated eCG mutants (T-betaalpha56, T-betacalpha and T-betacalpha56) as well as T-betaalpha. The biological roles of oligosaccharides at Asn(56) of eCG alpha-subunit and O-linked peptide of beta-subunit appear to be different in LH- and FSH-like activities in tethered-eCG.
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Affiliation(s)
- Kwan-Sik Min
- Laboratory of Cellular Biochemistry, Animal Resource Sciences /Veterinary Medical Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Japan
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